http://eloquentjavascript.net/ (has pdf download)
https://developer.mozilla.org/en/A_re-introduction_to_JavaSc...
Most JS books are geared towards browser scripting. I would still recommend "JavaScript. The Definitive Guide" by David Flanagan.
Also watch all the Crockford Videos on JS: http://video.yahoo.com/watch/111593/1710507
After that all you will ever need is:
* JavaScript: The Good Parts by Douglas Crockford (must have) * https://developer.mozilla.org/en/JavaScript/Reference (extensive, lots of examples and hints)